A Prospective Clinical Trial of Efgartigimod for New-Onset Generalized Myasthenia Gravis.

Introduction: Numerous studies have demonstrated that efgartigimod is effective in treating myasthenia gravis (MG) across various patient populations. However, there is limited evidence regarding its use in patients with new-onset acetylcholine receptor antibody-positive generalized MG (AChR-gMG). Therefore, this study aimed to investigate the real-world safety and effectiveness of efgartigimod in Chinese patients with new-onset anti-cholinergic receptor (AChR)- gMG.

Methods: This prospective study was conducted in 29 patients with new-onset AChR-gMG, with a three-month follow-up. The Myasthenia Gravis Activities of Daily Living (MG-ADL) score, Quantitative Myasthenia Gravis score, prednisone dose, laboratory data, and adverse events were assessed at every follow-up visit.

Results: At 4, 8, and 12 weeks, the mean change in MG-ADL scores was 8.13 ± 3.66, 7.41 ± 4.22, and 6.37 ± 4.67, respectively. Compared with the baseline, 96% (28/29) of patients achieved an MG-ADL response (defined as a decrease of ≥2 points), with a mean response time of 0.81 ± 0.53 weeks (5.67 ± 3.71 days). After one cycle, 52% (15/29) of patients achieved minimal symptom expression (MSE), while 41% maintained MSE at 12 weeks. Moreover, 89% and 72% of MG-ADL responders sustained for 8 and 12 consecutive weeks, respectively. Additionally, patients with thymomatous MG exhibited a poorer response to efgartigimod and required two infusion cycles. All patients were able to reduce their daily steroid dose, and the mean daily prednisone dose decreased by 10.73 mg per day. The treatment was well tolerated, and a few mild adverse events were reported.

Discussion: These results demonstrate the clinical significance of efgartigimod in patients with newonset AChR-gMG, achieving rapid symptom relief and steroid reduction. Additionally, the potential of efgartigimod to serve as a bridge treatment, facilitating a steady transition to long-term conventional immunosuppressive therapy, was demonstrated. Due to limitations in this study, such as a small sample size, larger randomized controlled trials are needed to validate.

Conclusion: Our study showed that efgartigimod is clinically beneficial and offers rapid symptom control in patients with new-onset AChR-gMG. A more aggressive application of efgartigimod in combination with corticosteroids may lead to a smoother therapeutic transition, which will further maintain favorable conditions.